1. Field of the Invention
The present invention relates generally to equipment for installing silt fencing, and more particularly, to a machine that includes trenching and post installation facilities.
2. Description of the Related Art
Silt fencing is used to control runoff and erosion at construction sites and other locations where runoff and erosion are noticed and must be controlled. Silt fencing is the typical temporary means of control that is applied to combat erosion and runoff. Silt fence installation has typically been a multi-step process requiring a trenching machine to cut a narrow trench in the ground, insertion of the bottom of the silt fence fabric into the trench, and subsequent installation of fence posts or stakes, to which the fence is finally attached, typically by stapling. The silt trench is generally backfilled and compacted to maintain the bottom of the silt fence in position.
Existing systems such as those disclosed in U.S. Patent Application Publication US20090110493A1 by Rorabaugh, et al., provide for formation of a slit trench with concurrent insertion of the silt fence fabric. However, subsequent manual installation of fence stakes is still needed and the fence must still be stapled to the stakes. Another system described in U.S. Patent Application Publication US20020192029 by Vreeland, includes a hydraulic stake driving device that is operated by the driver of the trench cutting tractor after the silt fence has been inserted in the ground. However, the silt fence still must be attached to the stakes subsequent to the stake installation.
Prefabricated silt fencing is available with stakes pre-attached at the factory, which eliminates the time-consuming stapling operation and provides for more uniform results, as variation in the quality of the staple attachment may be cause for inspectors to require corrective action. Further, some silt fence installations require a wide anchorage trench that secures the bottom of the silt fence at a specified depth by extending the bottom of the silt fence along the bottom of the trench. The posts are installed in the trench, as well. Backfilled soil retains the bottom of the silt fence at its installed position by virtue of the weight of the soil and compaction. Existing systems that are designed for installation of prefabricated silt fencing, such as the system disclosed in U.S. Pat. No. 6,158,923, form a trench by pushing a plow having a rectangular profile through the earth and then automatically installing the fence stakes. The result is that variations in inclination of the surrounding earth, and thus the motive vehicle, will be reflected in the inclination of the installed stakes and the inclination of the bottom and sides of the trench, which also reduces the trench depth along one side. Plows are also sensitive to soil and rock conditions, and may ride out of the trench or fail if the resistance of the ground is too high, such as when a large root or rock is encountered.
Therefore, it would be desirable to provide silt fence installation equipment and methods that are compatible with wide anchorage trench installations in a variety of soil conditions and that can install prefabricated silt fencing vertically and form a trench having vertical sides and a flat bottom. It is further desirable to streamline the process of trenching, post installation and backfilling so that efficiency of the silt fence installation process is improved.